Monthly Archives: February 2012

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Evolution 2012, the biggest annual meeting of evolutionary biologists, is in Ottawa this year. It’s time to start planning for the trip, and my fellow Tiffin Lab postdoc John Stanton-Geddes was just checking out the accommodation options around the convention centre when he noticed something

This week at the collaborative science blog Nothing in Biology Makes Sense!, contributor Devin Drown discusses a new study of bacterium-on-bacterium violence:

The bacteria produce chemical weapons, bateriocins, which can broadly harm other isolates, but relatives are left unharmed. These chemical weapons can be classified as spiteful: in the process of harming others they also harm the focal individual. This self-harm comes from the cost of making the chemical weapon. Others have labeled this antagonistic trait a greenbeard gene.

To learn what a bacterial chemical weapon has to do with what might otherwise sound like an overenthusiastic celebration of Saint Patrick’s Day—and how both might explain the diversity of living populations, read the whole thing. ◼

Oh, sure, your average conservative will insist his belief system is based upon a passion for the free market and limited government, but that’s mostly a cover story. Instead, the vast team-building exercise that has driven the broadcasts of people like Rush and Hannity and the talking heads on Fox for decades now has really been a kind of ongoing Quest for Orthodoxy, in which the team members congregate in front of the TV and the radio and share in the warm feeling of pointing the finger at people who aren’t as American as they are, who lack their family values, who don’t share their All-American work ethic.

The finger-pointing game is a fun one to play, but it’s a little like drugs – you have to keep taking bigger and bigger doses in order to get the same high.

It started out in college. You know, just experimenting with it. But he liked it. He liked how it made him feel.

For a while it was just recreational — weekends and parties and rallies and that kind of thing. But soon he was hanging out with some pretty hard-core users, with the kind of people who took offense all the time. They didn’t need a reason or an excuse, it was just what they did. It was who they were. Soon he found he couldn’t get through the day without it.

In the GOP race, Taibbi’s seeing the logical outcome of the impulse Slacktivist has been calling self-destructive for years. ◼

Spoiler alert: Indy (and the franchise) wouldn’t have survived, in the real world. But exactly how Professor Jones would most likely meet his end is a much more enjoyable question. Here’s a tiny bit:

Sadly, the lead and steel shielding which the authors intend to protect their protagonist from ionizing radiation can itself become a source of it. While beta decay constitutes a relatively small portion of the average nuclear device’s output, what little sprinkle the Frigidaire receives it will transmute, in kind, into an X-ray bath for its inhabitant. It’s sort of like the way a Russian Sauna works, but instead of hot coals there’s a nuclear explosion, and instead of steam there’s a burst of X-rays, and instead of a wood hut it’s a Frigidaire, and also you’re dead. [Link sic.]

As additional evidence of Shechner’s scientific bona fides, he presents the whole analysis in the persona of the third reviewer. I don’t think I’ve enjoyed a takedown of one of George Lucas’s late-career cinematic catastrophes so much since Anthony Lane wrote, in reference to Yoda’s diction in Revenge of the Sith, “break me a fucking give.” ◼

So, lately there’s been a storypercolating through the gay and gay-friendly blogosphere, about a church that went to Chicago Pride to apologize:

I spent the day at Chicago’s Pride Parade. Some friends and I, with The Marin Foundation, wore shirts with “I’m Sorry” written on it. We had signs that said, “I’m sorry that Christians judge you,” “I’m sorry the way churches have treated you,” “I used to be a bible-banging homophobe, sorry.” We wanted to be an alternative Christian voice from the protestors that were there speaking hate into megaphones.

There’s even this photo of a guy in short shorts, so overcome with emotion at this “alternative Christian voice” that he stepped out of the parade for a hug. It sounds beautiful—as they say, almost too good to be true.

It doesn’t matter how polite you are when you say it—the position that same-sex relationships are inherently sinful, that gays and lesbians are somehow undermine the “sanctity” of other people’s relationships by loving the people we do, is inherently and inexcusably hateful. It’s the root of the more overt bullying and hatred that the Marin Foundation is ostensibly repenting for. There are lots of Christians who have truly repented and repudiate fundamentalist homophobia, and all of them acknowledge this link: Fred Clark and John Shore are two sterling examples; or see the religious groups who are rallying against Minnesota’s proposed constitutional ban on marriage equality.

I can certainly understand why the Marin Foundation story keeps popping up; it’s a poignant one, and it’s one we’d like to see happen for real. And stories like it are happening for real, all the time and all over the country. But Marin’s flashy, two-faced stunt at Chicago Pride distracts from quieter stories of real repentance, love, and acceptance. ◼

When evolutionary biologists think about sex, we often think of parasites, too. That’s not because we’re paranoid about sexually transmitted infections—though I’d like to think that biologists are more rigorous users of safer sex practices than the general population. It’s because coevolution with parasites is thought to be a major evolutionary reason for sexual reproduction.

This is the Red Queen hypothesis, named for the character in Lewis Carroll’s Through the Looking Glass who declares that “it takes all the running you can do to keep in the same place.” Parasite populations are constantly evolving new ways to infest and infect their hosts, the thinking goes. This means that a host individual who mixes her genes with another member of her species is more likely to give birth to offspring that carry new combinations of anti-parasite genes.

But although sex is the, er, sexiest prediction of the Red Queen, it’s not the whole story. What matters to the Red Queen is mixing up genetic material—and there’s more to that than the act of making the beast with two genomes. For instance, in the course of meiosis, the process by which sex cells are formed, chromosomes carrying different alleles for the same genes can “cross over,” breaking up and re-assembling new combinations of those genes. Recombination like this can re-mix the genes of species that reproduce mostly without sex; and the Red Queen implies that coevolution should favor higher rates of recombination even in sexual species.

That’s the case for the red flour beetle, the subject of a study just released online by the open-access journal BMC Evolutionary Biology. In an coevolutionary experiment that pits this worldwide household pest against deadly parasites, the authors show that parasites prompt higher rates of recombination in the beetles, just as the Red Queen predicts.

The red flour beetle, Tribolium castanaeum, is named for its predilection for stored grain products. This food preference makes the tiny beetles particularly easy to raise in the lab, where they’ve been useful enough as a study organism to rate a genome project, which was completed in 2008.

Tribolium castanaeum reproduces strictly sexually. But, like any other biological trait or process, the beetle’s rate of recombination can vary, and evolve. And, as I’ve explained above, the Red Queen suggests that selection by parasites should favor higher rates of recombination. So the authors of the new study set experimental populations of the beetle to evolve either in parasite-free habitats, or under attack by Nosema whitei, a protozoan that infects and kills flour beetle larvae.

The team started experimental populations of beetles (fed on organic flour, natch) in each of the two treatments with eight different genetic lines, maintaining them at a constant population by collecting 500 beetles at the end of each generation to start the next generation. To make the coevolution treatment coevolutionary, the authors also transferred spores of the parasite produced in the previous generation to infect each new generation of beetles.

After 11 generations of coevolution, the authors sampled male beetles from four of the experimental populations in each treatment, and mated them with females from the same genetic line. By collecting the genotypes of the sampled males for a small number of strategically chosen genes, and comparing them to the genotypes of the males’ offspring, it was then possible to identify recombination events—offspring who had combinations of alleles at different genes that weren’t seen in their fathers.

And, indeed, the frequency of recombination—the proportion of offspring whose genetics showed signs of recombination events when compared to their fathers—was greater in the experimental lines that coevolved with Nosema whitei.

That’s a fairly remarkable result for a simple, relatively short selection experiment, and to my knowledge it’s the first of its kind to deal with recombination, as opposed to sex. There are a few study systems in which natural populations show signs of coping with parasites by having more sex, including C.J.’s favorite mollusks, and there is one good experimental example in which the worm Caenorhabditis elegans evolved to reproduce sexually when confronted with bacterial parasites. But this study marks a new bit of empirical support for the Red Queen: coevolution acting to boost the gene-mixing benefits of sex. ◼

Paul’s “We the People Act,” which he introduced in 2004, 2005, 2009, and 2011, explicitly forbids federal courts and the Supreme Court of the United States from ruling on the constitutionality of a variety of state and local laws. That includes, among other things, “any claim based upon the right of privacy, including any such claim related to any issue of sexual practices, orientation, or reproduction.” The bill would let states write laws forbidding abortion, the use of contraceptives, or consensual gay sex, for example.

Maybe it’ll come in handy, having these two items together in one place?

There have been a number of different mechanisms of selection that have been proposed to explain sex: host-parasite interactions (Bell 1982), elimination of deleterious alleles (Mueller 1964), and various forms of selection (Charlesworth 1993; Otto and Barton 2001; Roze and Barton 2006). However, none of these alone are able to theoretically overcome the two-fold cost of producing males, so many biologists have started taking a pluralist approach (West et al. 1999; Howard and Lively 1994) and combing one or more of the advantages to being sexual in an effort to understand why the birds do it, the bees do it, and even educated fleas do it.

To learn how a new study revives the longstanding “Red Queen” theory—that sex is beneficial because sexually-produced offspring are more likely to carry genes that can help fight off parasites—go read the whole thing. ◼